In one embodiment, a method receives a downstream signal and an upstream signal in a same frequency band. The downstream signal and the upstream signal are separated into a first path and a second path. The downstream signal using the first path and the upstream signal using the second path are amplified in an analog domain. The method isolates the downstream signal and the upstream signal from one another and sends the downstream signal downstream to a subscriber device and sends the upstream signal towards a full duplex node.

A capacitor circuit includes a first terminal, a first to a third transistor and a first capacitor. The first transistor includes a first terminal configured to be coupled to a first current source and the first terminal of the capacitor circuit, and a second terminal coupled to a reference voltage terminal. The second transistor includes a first terminal configured to be coupled to a second current source, a second terminal coupled to the reference voltage terminal, and a control terminal coupled to the first terminal of the second transistor and a control terminal of the first transistor. The third transistor includes a first terminal configured to be coupled to a third current source and the first terminal of the first transistor, a second terminal coupled to the reference voltage terminal, and a control terminal coupled to the control terminal of the second transistor. The first capacitor includes a first terminal coupled to the first terminal of the capacitor circuit, and a second terminal coupled to the control terminal of the first transistor.

An integrated isolator circuit for isolating receiver and transmitter in a Time-Division Duplex transceiver is disclosed. The integrated isolator circuit comprises a first node, a second node and a third node. The integrated isolator circuit further comprises a first capacitor connected in series with a first switch and connected between the first and second nodes. The integrated isolator circuit further comprises a first inductor connected between the first and second nodes and a second capacitor connected between the second node and the third node. The first switch has an on state and an off state, and the integrated isolator circuit is configured to have a different impedance at a certain operating frequency by controlling the state of the first switch.

A front-end module that uses a carrier aggregation scheme in which Band, which is selected from a low-frequency band group, and Band, which is selected from a high-frequency band group, are used simultaneously for communication includes a plurality of signal paths that connect a power amplifier module to an antenna element, and an antenna switch module that switches connection between the antenna element and the plurality of signal paths. Harmonics of Band have frequencies that are included in Band. The front-end module further includes a switch element disposed in a TDD transmission path.

A front-end module that uses a carrier aggregation scheme in which Band, which is selected from a low-frequency band group, and Band, which is selected from a high-frequency band group, are used simultaneously for communication includes a plurality of signal paths that connect a power amplifier module to an antenna element, and an antenna switch module that switches connection between the antenna element and the plurality of signal paths. Harmonics of Band have frequencies that are included in Band. The front-end module further includes a switch element disposed in a TDD transmission path.

According to one embodiment, a wireless device includes a plurality of transmission/reception units and a controller. The each of the plurality of transmission/reception units includes an antenna and is configured to transmit/receive a wireless signal by the antenna. The controller individually controls a frequency of the wireless signal transmitted/received by each of the plurality of transmission/reception units.

According to one embodiment, a wireless device includes a plurality of transmission/reception units and a controller. The each of the plurality of transmission/reception units includes an antenna and is configured to transmit/receive a wireless signal by the antenna. The controller individually controls a frequency of the wireless signal transmitted/received by each of the plurality of transmission/reception units.

Embodiments provides a radio network entity and the method thereof for improving filtering performance in a time division duplexing radio communication system, the radio network entity comprises: a first filter, which is configured to perform a first type of filtering for a signal to be transmitted to, or received from a device in the radio communication system through a radio interface, with a common filtering requirement for transmitting and receiving fulfilled, a second filter, which is configured to perform a second type of filtering for the signal to be transmitted to the device, with additional filtering requirement for transmitting besides the common filtering requirement fulfilled; and a third filter, which is configured to perform a third type of filtering for the signal received from the device, with additional filtering requirement for receiving besides the common filtering requirement fulfilled.

Embodiments provides a radio network entity and the method thereof for improving filtering performance in a time division duplexing radio communication system, the radio network entity comprises: a first filter, which is configured to perform a first type of filtering for a signal to be transmitted to, or received from a device in the radio communication system through a radio interface, with a common filtering requirement for transmitting and receiving fulfilled, a second filter, which is configured to perform a second type of filtering for the signal to be transmitted to the device, with additional filtering requirement for transmitting besides the common filtering requirement fulfilled; and a third filter, which is configured to perform a third type of filtering for the signal received from the device, with additional filtering requirement for receiving besides the common filtering requirement fulfilled.

An in-vehicle communication system can communicate with a public communication network through the use of communication modules, and can use, as the communication modules, an in-vehicle communication module that is mounted in a vehicle and an outside communication module other than the in-vehicle communication module. The in-vehicle communication system is equipped with a communication state confirmation unit that transmits data to the public communication network and receives data from the public communication network through the use of the outside communication module, and that confirms a communication state between the outside communication module and the public communication network, and a module selection unit that selects the communication module to be used, from between the in-vehicle communication module and the outside communication module, based on the communication state confirmed by the communication state confirmation unit.